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At least 631 records · Page 35Linked to original sources
PubMed1983

[Blastocystis hominis: morphological study using optical and electron microscopy].

Blastocystis hominis is a member of the phylum Protozoa as described by Zierdt et al. Despite the complexity of its yet not well defined biological cycle, Blastocystis was found to possess all the structures characterizing protozoans. The physiochemical and biological growth conditions are those of many protozoans. The high degree of cell differentiation is probably due to the existence of two reproduction modes.

Fungi↗
PubMed1981

Analysis of inorganic fiber concentrations in biological samples by scanning electron microscopy.

Analyzing fibers with electron microscopic techniques involves several preparation steps, especially during the analysis of fibers in human tissue. The influence of these steps on the analytical result was studied in detail. Fiber number was unaffected by the mild sonication of fiber suspensions analyzed with scanning electron microscopy. Significant fiber losses appeared during the filtration of fiber suspensions through 0.8-micrometer pore-size Nuclepore membranes. Shrinkage of the tissue during dry ashing broke lung fibers and consequently increased the fiber concentration and affected the fiber length distribution. Dry ashing, however, removed more of the organic debris than wet ashing; thus specimens prepared with dry ashing were more suitable for scanning electron microscopic analysis. A fairy good correlation was demonstrated for the analysis of fibers with scanning and transmission electron microscopy.

Asbestos↗
PubMed1992

Nature and localization of avian lens glycogen by electron microscopy and Raman spectroscopy.

Electron microscopy confirms the presence of a high concentration of glycogen particles in the lens nuclear region of birds of flying habit such as the ring-neck dove and pigeon. This observation is consistent with Raman spectroscopy. The glycogen particles in the dove lens, which are approximately 35 nm in diameter, are classified as beta type particles. Although this type has been previously characterized by high rates of glycogen turnover in other tissues, its localization in the lens nucleus indicates that it may serve a structural function rather than as a storage depot of carbohydrate in the lens. In a comparative electron microscopy study, glycogen particles were not observed in the chicken lens.

Animals↗
PubMedDate not supplied

Observations on embryonic chick-bone crystals by high resolution transmission electron microscopy.

High resolution transmission electron microscopy of bone mineral at a vary early stage in its deposition in embryonic chick frontal bone demonstrates crystals of 2-2.5 nm thickness and a profile up to 40 nm long. They appear in groups which may show as few as one or two crystals. Associated with the crystals is a less dense amorphous material. Using specimen tilting, the change in crystal appearance indicates that crystals are tablet-shaped (rectangular) rather than rod-shaped. The amorphous material may be tablet-shaped crystals in orientations which are not dense enough to register as crystals in the image. Truly amorphous mineral does not show by bright-field electron microscopy, but preliminary results indicate that the dark-field technique may prove to be useful in imaging amorphous mineral provided that sections can be cut thinly enough and that precautions are taken during specimen preparation to avoid mineral loss. Crystals have been located in various parts of the osteoid zone and were not associated specifically with any one component. Rapid processing using anhydrous techniques must be used to avoid the possibility of artefactually altering the in vivo conditions of the mineral at the time of excision of the specimen.

Animals↗
PubMed1999

Analysis of calcitonin gene-related peptide (CGRP)-containing nerve fibres in the rat spinal cord using light and electron microscopy.

Calcitonin gene-related peptide (CGRP) content in areas surrounding the central canals of cervical, thoracic, lumbar and sacral spinal cords of rats were investigated by light microscopy, conventional transmission electron microscopy (CTEM) (100-200 kV) and high-voltage transmission electron microscopy (HVTEM) (1000 kV) using immunocytochemistry. Tissues were examined using either the peroxidase-antiperoxidase technique or an immuno-cryoultramicrotomy technique. Light microscopically, more intense CGRP localization was observed ventral to the central canals in the lumbar and sacral cord compared with the dorsal area in the same regions. HVTEM revealed that high levels of CGRP labelling were found adjacent to the basal side of ependymal cells ventral to the central canal. Analysis using CTEM operated at 200 kV demonstrated that the CGRP immunoreactivity was present within unmyelinated nerve fibres in the vicinity of the basal side of ependymal cells ventral to the central canal. Immuno-cryoultramicrotomy revealed that immuno-gold particles indicating CGRP labelling were localized on vesicle-like electron-dense bodies in unmyelinated and some fine caliber myelinated nerve fibres. Existence of CGRP as a primary afferent marker in the area surrounding the central canal suggest that there may be an intimate relationship between the modulation of nociceptive information and the area surrounding the central canal in rat spinal cord.

Animals↗